It actually probably wouldn't be considered an Arena roleplay, ironically. Arena is sort of a catch-all term for RP based around player vs player combat in a play by post medium. You could still run this here, but people prefer one shots rather than lengthy narratives for the most part. 

If you were just planning to roleplay fights between superhuman teenagers then you might garner some interest here, but if you want to tell what is essentially a slave rebellion/Spartacus narrative, you might be better off in free or casual.